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High-speed baby stars swarm around Milky Way's Sagittarius A*

At the heart of our galaxy, the supermassive black hole Sagittarius A* draws in newly discovered young stellar objects (YSOs) that circle it at incredible speeds.

Observations have revealed that these infant stars, located near Sagittarius A*, follow similar orbits to previously known young stars, forming a distinct pattern around the black hole.

Sagittarius A* and young star formation

Recent research indicates that Sagittarius A* influences the formation of these swarming stars.

The latest study, led by researchers from the University of Cologne, involved contributions from multiple institutions including universities in Germany and the Czech Republic, and the Max Planck Institute for Radio Astronomy.

About three decades ago, astronomers discovered highly dynamic stars near Sagittarius A*, known as S stars, which orbit the black hole at speeds of several thousand kilometers per hour. The stars complete their orbits within a few years.

The young age of the S stars puzzled scientists, who expected only old, dim stars in such a hostile environment.

Technological advancements and new discoveries

Advancements in telescope technology and prolonged observations of the Milky Way’s galactic center have raised new questions.

In 2012, researchers found an object initially thought to be a gas cloud, potentially consumed by the black hole. Though this theory remains unconfirmed, evidence suggests it might be a YSO surrounded by a dusty cloud.

In addition to the S stars, the Cologne-led team has identified about a dozen objects near Sagittarius A* with similar properties. These newly found objects are significantly younger than the known high-speed stars.

“Interestingly, these YSOs exhibit the same behavior as S stars. This means that the YSOs circumnavigate the supermassive black hole with speeds of several thousand kilometers per hour in a few years,” explained study co-author Dr. Florian Peißker.

“The S stars were found to be surprisingly young. According to conventional theories, the additional presence of a stellar kindergarten composed of YSOs is completely unexpected.”

Chaotic yet organized patterns

Initially appearing as a chaotic swarm of bees, these high-velocity YSOs and S stars actually follow specific, organized formations. The research shows that both YSOs and S stars are arranged systematically within three-dimensional space.

“This means that there are specific preferred star constellations. The distribution of both star variations resembles a disk, which gives the impression that the supermassive black hole forces the stars to assume an organized orbit,” explained Dr. Peißker.

These findings shed light on the dynamic environment around Sagittarius A* and challenge existing theories about star formation and behavior near supermassive black holes.

The discovery of these young stars orbiting so closely to Sagittarius A* opens new avenues for understanding the complex interactions between black holes and their stellar neighbors.

More about Sagittarius A*

Sagittarius A* is situated in the constellation Sagittarius, approximately 26,000 light-years from Earth. The black hole has a mass about 4.1 million times that of the Sun.

Despite its enormous mass, Sagittarius A* is relatively small in size, with a diameter roughly equal to the distance between the Earth and the Sun.

The existence of Sagittarius A* was inferred through the observation of the orbits of stars near the galactic center, which revealed the presence of a massive, invisible object exerting a strong gravitational pull.

The Event Horizon Telescope (EHT) project captured an image of its event horizon, providing direct visual evidence of the black hole.

Sagittarius A* plays a crucial role in our understanding of black holes and the dynamics of galaxies. Its study helps astronomers learn about the behavior of matter in extreme gravitational fields and the processes occurring in the vicinity of black holes.

The region around Sagittarius A* is a hub of high-energy activity, with gas and dust being pulled in at high speeds, generating intense radiation that can be observed across various wavelengths.

The study is published in the journal Astronomy & Astrophysics.


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